A multi-center study based in Canada has determined a stronger relationship between aging and ganglion cell layer (GCL) thickness compared with the rim or peripapillary retina nerve fiber layer (RNFL).

The study included one eye of 246 subjects equally divided into decade groups from ages 20 to 90. Of the six inner layers of the macula, there was a statistically significant decrease with age of only the GCL, inner plexiform layer and inner nuclear layer thickness with rates of -0.11μm/y, -0.07μm/y and -0.03μm/y, respectively. These rates corresponded to 2.92%, 2.15% and 0.88% loss per decade, respectively.

The researchers found the minimum neuroretinal rim width and peripapillary RNFL thickness decreased at a rate of -1.22μm/y and -0.20μm/y, respectively, corresponding to 3.63% and 2.04% loss per decade. However, the association of GCL thickness change with age was approximately twice that of minimum neuroretinal rim width and RNFL thickness.

The researchers believe that age-related structural changes are most accurately measured with macular OCT imaging and propose that the macular GCL and peripapillary RNFL measurements more accurately reflect axonal loss.